Photoinduced ring-opening polymerization of N carboxyanhydrides for the preparation of cross-linked polypeptide gels
Cross-linked polypeptides are a versatile class of materials with significant potential for a wide range of biomedical applications. A convenient method for preparing synthetic polypeptide materials is the ring-opening polymerization (ROP) of N‑carboxyanhydrides (NCAs). Our aim was to introduce light as a trigger for the ROP of NCAs to achieve spatial and temporal control over the polymerization, providing a foundation for additive manufacturing of polypeptides.
In this publication, we present a photochemical approach for the ROP of NCA monomers to prepare covalently cross-linked synthetic polypeptide gels using light. We apply 2‑nitrobenzyl carbamate as a photocaged amine (base), where the switch in its activity after illumination is key in controlling the ROP of NCA. The released dibutylamine, as a basic species, deprotonates the NCA and thereby initiates polymerization. This approach is demonstrated on the ROP of γ-benzyl-L-glutamate NCA to produce covalently cross-linked polypeptide gels. We demonstrate excellent two‑dimensional spatial and temporal control over gelation, further enhanced by the use of an acid inhibitor that prevents overcuring caused by diffusion of active species from the illuminated region.
The development of photoinduced polymerization and cross-linking of NCAs offers significant advantages in polypeptide synthesis, particularly when gels with well-defined and complex shapes are required. This approach therefore holds great potential for further applications in additive manufacturing.
The article was published in Angewandte Chemie International Edition and authored by Ana Kočman, Dr David Pahovnik, Dr Ema Žagar, and Dr Petra Utroša from the department of Polymer Chemistry and Technology at the National Institute of Chemistry.
More information: doi.org/10.1002/anie.202521891
Contact: petra.utrosa@ki.si